Production of decorative glass



Julyza' w41. w. o. um 2,251,144

PRODUCTION or DECORATIVE @Lass Filed April 14, 193:3'l

VvE/v To@ Wil- ,am ,0. L. r 1v. s

Patented July 29,1941

UNITED STATES PATENT OFFICE PRODUCTION F DECORATIVE GLASS William 0.Lytle, New Kensington, Pa., assignor to vPittsburgh Plate Glass Company,Allegheny County, Pa., a corporation of Pennsylvania Application April14, 1938, Serial No. 201,961

3 Claims.

The present invention relates to the production of decorative glass, andmore particularly to a decorative glass having' a double layer of glazeon one surface thereof. v

The primary object of my invention is to provide an opaque glass havingon one surface thereof layers of two differently colored glazes.

Another object of my invention is to provide a process of producingdecorative glass having at least two different layers of glaze on onesurface thereof which will appear as one colorwhen viewa colored glaze2is formed and another layer of glaze 3 of contrasting color is appliedover layer 2 by methods which will be hereinafter described. An ornamentor design Il may be formed in the glazed surface of the product bypartially removing a portion of the glazed surface 3. Any desiredornamental effect may be provided by cutting through the glaze 3 by anydesired means, such as by sand-blasting, or etching the surfaces 3, and2. l

The present invention is based upon the discovery that an opaque glasshaving a decorative appearance and which appears as one color whenviewed by reflected light and as another color when viewed bytransmittedlight may be produced by applying glazes of two differentcolors to one surface of a glass sheet.

A double layer of glaze may be suitably applied to a glass sheet by anyone of 'three different processes, such as by enameling, by the drawingprocess, or by the rolling process.

According to the enameling process, the glass surface to be decoratedmay have the desired colors painted upon the surface. Such coloringmatter may be easily scratched from the glass so that it is moredesirable to utilize a more permanent method of enameling which consistsin painting or printing the glass surface with a suitable glaze orenamel in the form of a slip, as before, and then drying the glass, andplacing it in a suitable furnace and ,heating it for a short time Itheglass.

A carrying medium for the powdered enamel. When the coloring agent isheated in the furnace it melts to form a true glaze on the surface ofThe following are some of the prinv cipal coloring agents which may beused:-

Yellow-barium chromate, lead chromate, ura- ,nium compounds, orantimony-lead compound.

Red-basic lead chromate, or ferrie oxide.

Brown-ferrie oxide, with zinc, nickel, and cobalt oxides as toningagents.

Blue-cobalt oxide, toned by the oxides of aluminum, zinc or chromium. A

Black-cobalt oxide with ferric oxide or man-` ganese dioxide. v

Green-copper oxide with potassium bichromate or chromic oxide withaluminum, cobalt, or iron oxides for toning.A

White-stannic oxide, zirconium oxide, or finely-ground porcelain.

The enamels used may be of two classes, opaque coloring enamels, ortransparent enamels. For the opaque enamels, suitable uxes are: (l) Sand30 parts, red lead 80 parts; ror (2) Sand 40- parts, red lead parts,borax 20 parts. For red, brown, and light blue colors the flux isgenerally first melted, cooled by pouring into water, and finelyground,- and then mixed with the coloring agent in the proportion ofabout thirty of ux to one of color.

The colors mentioned above may be mixed to form any desired shade orblend of colors.

According to the second process mentionedMr above, the layers of glazemay be formed on the glass sheet by the drawing process iri an ordinarysheet glass machine, such as that ofA Slingluif or Colburn. In thisprocess, the coloring material in the form of colored glass in molten orpowdered form is fed onto the surface of the bath adjacent the line ofdraw of the sheet, or, if dei;win sired, the coloring material may beapplied to the .surface of the glass sheet by the leer rollers as thesheet passes through a vertical leer. In such a case, the lower pair ofleer rollers may be employed to apply a glaze of high melting pointwhile an upper pair of leer rollers may be utilized to apply a secondlayer of glaze of colored material having a lower melting point than themelting point of said rst-nientioned glaze.

According to the third process mentioned above, the layers of glaze maybe formed on the glass sheet by the rolling process, such as is clearlydescribed in United States Patent No, 1,529,- 947, to Ira H. Freese. Inthis process, the coloring material, preferably in several hoppers, isfed onto the molten surface of a glass sheet as it is passed through ahorizontal leer. In such a case, the coloring material of differentmelting points is placed in the hoppers so that the high melting pointglaze is applied rst, and the low melting point glaze is applied secondto the glass sheet.

The coloring matter utilized in the two abovedescribed processes isordinarily in the form of colored frit. This frit may be of variouskinds, but is ordinarily a nely divided glazing material having amelting point of not more than about 1200" F. mixed with suitablecoloring ingredients so that when fused, it forms a glaze or enamelwhich constitutes the surface layers of the glass sheet. This glaze ismade up of ingredients proportioned so that the material after it isfused onto the glass sheet has substantially the same coecient ofexpansion as the body of the glass sheet. It is preferably of granulesof substantial size rather than dust, a dust-like material beingobjectionable because of its dissipation to f the atmosphere during thefeeding operation when the colored material is applied to the redhotglass sheet.

An opaque glass having two layers of ornamental glaze of two differentcolors may be produced by any of the above-described processes and thebody I may be made of opaque material blasting, to expose a portion ofthe surface of the inner layer of glaze 2, or if desired, the layer 2may be removed to expose the surface of sheet I. Also, when contrastingor blending colors are used to form the two different layers of glaze 2and 3, it is possible to produce a glass which appears as one color whenviewed by reflected light and as another color when viewed bytransmitted light. Also, the glass product may be annealed, if desired.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations should be understoodtherefrom, but it should be construed as broadly as permissible in viewof the prior art.

WhatI claim is:

1. A -process .of producing decorative glass which comprisesdistributing a uniform layer of unfused colored vitreous material ofcomparatively high melting point over one surface of a sheet of glasscontaining sufcient heat to fuse the added vitreous material,distributing a second uniform layer of unfused vitreous material of a byincorporating into the batch from which the glass is made suitableopacifying agents such as sodium silicon uoride or fluorspar.

Various ornamental eiects, such as the ornament 4 in the drawing, may beproduced by placing any desired pattern over the outer layer of glaze 3and removing a portion of such glaze by any suitable means, such as byetching or sanddifferent color and having a comparatively low meltingpoint over the rst layer of added vitreous material, while the coatedsheet of glass retains sufficient heat to fuse the second layer, and`completely cooling the doubly coated sheet of glass.

2. A process of producing decorative glass which comprises applying alayer of colored frit of comparatively high melting point to one surfaceof a newly formed glass sheet, containing sufficient residual heat tofuse the frit, and then applying immediately a second layer of coloredfrit of a lower melting point than that of the frit first applied to thesheet over said firstmentioned layer of colored frit while the sheetretains suiiicient heat to fuse the second layer of frit.

3. A process as defined in claim 2, wherein the glass sheet towhich thecoating layers of frit are applied is produced as a continuous ribbon.

WILLIAM O. LYTLE.

